If you have conducted a study using the regression-discontinuity design, how would you tell if your treatment had an effect?
A) by looking at the data to see if the regression line of the posttest scores differs from the regression line of pretest scores.
B) by statistically analyzing the data using Analysis of Variance.
C) by comparing the pretest scores with the posttest scores to see if there was a significant change.
D) by determining if there is a discontinuity in the regression line for the people above and below the cutoff score.

Question

Quizplus · Accepted Answer

In a regression-discontinuity design, the key indicator of a treatment effect is a discontinuity or a sharp change in the regression line at the cutoff score, which separates participants who received the treatment from those who did not. This design does not primarily rely on comparing pretest and posttest scores or the overall change in regression lines but focuses on the specific discontinuity at the threshold.

If You Have Conducted a Study Using the Regression-Discontinuity Design